If bubbles come into a measuring section of a liquid material discharge device, the movement of a plunger cannot be precisely transmitted to a liquid material and the liquid material cannot be discharged with high accuracy.
As one example of a debubbling mechanism for the liquid material discharge device, the applicant has developed a liquid material discharge device in which a debubbling hole is formed in a plunger head (Patent Document 1).
In the device described in Patent Document 1, an ordinary discharge operation is performed in a state where an upper larger-diameter portion of a valve rod is slidably fitted to an upper inner space of a plunger rod, and a top surface of the valve rod is fixedly pressed by a setting screw that is screwed to a plunger support. On the other hand, a debubbling operation is performed by loosening the setting screw that presses the top surface of the valve rod.    Patent Document 1: Japanese Patent Laid-Open No. 2003-190871